Closed exhaust box for silencing internal-combustion engines



Patented June 3, 1930' UNITED STATES PATENT OFFICE 'WILLIBIED FfiRSTEL, OF SPANDA U, GERMANY Application filed June 18, 1927, Serial No. 199,375, and in Germany October 12, 1928.

At the present time traific authorities in many countries are making an effort to find means for doing away with the noises produced by the exhaust of motor cycles, automobiles, motor boats and'the like, so that the din of traflic may be brought withinreasonable limits and the air kept reasonably pure.

Now in order to do away with the loud noises produced by the exhaust and by the explo sions in motor vehicles, boats and the like, and in short in all internalcombustion engines, silencing exhaust boxes of the most varied kinds, both with and without nozzles, have been placed on the market.

As compared with open exhaust, however, no substantial advantages have up to the present been obtained. On the one hand when a fairly effective silencing action has been obtained, the interior of the exhaust box has had to be equipped with such great resistance to the passage of the gases as to exert a braking effect upon the motor, and thereby enormously diminish the eiiiciency thereof.

Sometimes the braking effect has amounted to 10 per cent. or more of the power of. the

englne, so that the owner has dismantled the exhaust box as soon as possible after the 0111- cial passing of the vehicle, since the fuel consumption was too high in comparison with the power of the engine. In the case of other constructions, moreover, although the braking effect has been less, the degree of silencing has also had to be less as well. Taking them all in all it has been found that the exhaust box silencers hitherto used have not adequately and economically fulfilled the purpose for which they have been intended.

The present invention is for the purpose of obviating the above-mentioned disadvanhate the braking action, and. secondly by suit-- tages, firstly by avoiding any throttling in the interior of the exhaust box, so as to elimiable construction to get rid of the disturbing explosion and exhaust noises. The invention utilizes the device known in itself of emgloying nozzles in the interior of the silencer.

pecialfeatures of the invention consist in a novel-construction and arrangement of the inlet and outlet nozzles,"and furthermore in mounting the nozzles resiliently.

motor cycles, motor able material.

a are to be so'selected that The invention is diagrammatically illustra-ted by way of example in the accompany- 111% drawings, wherein igure 1 is a longitudinal section of the device,

Figure 2 a longitudinal section in a plane at right angles to that of Figure '1, and

Figure '3 a cross section onthe line III III in Figure 2.

The exhaust gases coming from the cylin-- der pass through a connecting pipe. 0 into the exhaust box silencer. They flow through a tube f, which may consist of round or other suitable material, and leave the same through a'nozzle 12. the cross section of which difiers in form from that of the inlet pipe, and V which may preferably be bent at an angle approaching 90 to the axis of the pipe.

mm the nozzle n the gases flow into the actual exhaust box casing a. The exhaust box may consist of sheet iron or other suit- The cross section and shape of the casing the gases cannot take up centrifugal movements therein. This result may for example be obtainedby making the casing of angular cross sectlon and providing it with longitudinal ribs 1) in the interior to act as bafile plates. The arrangement of such ribs is of course advantageous with other cross-sectional forms of V the exhaust box.

The gases leave the casing through a second nozzle n and the exhaust pipe 9 and a pipe d connected therewith, and then escape to the atmosphere. p

The silencing effect can be appreciably improved by arranging the nozzles resiliently or oscillatably. For this purpose the inlet and =outlet pipes f and g consist according to the drawing of helical spring pipes.

The nozzle n and the nozzle M, if they are to extend right to the centre of the exhaust box, must touch one another with a light pressure, so that when the nozzles are set in oscillation during the working of the motor,'in consequence of the movability of the resilient pipes, only a frictional effect is produced but no knocking together.

'What I claim is 1. A closed exhaust silencer for internal combustion engines, comprising a casing, a resilient inlet pipe for admitting exhaust gases to said casing, a resilient outlet pipe for discharging exhaust gases from said casing, and a nozzle on the inner end of each of said pipes, each of said nozzles being fiattened and bent aside.

2. A closed exhaust silencer for internal combustion engines, comprising a casing, a resilient inlet pipe for admitting exhaust gases to said casing, a resilient outlet pipe for discharging exhaust gases from said casing, and a nozzle on the inner end of each of said pipes, each of said nozzles being formed with a flattened and elongated aperture, and being bent aside so as t: be directed towards the side Walls of the casing.

3. A closed exhaust silencer for internal combustion engines, comprising a casing, an inlet pipe for admitting exhaust gases to said casing, an outlet pi e for discharging exhaust gases from sai casing, a nozzle on the inner end of each of said pipes, each of said nozzles being flattened and bent aside, and longitudinal ribs on the internal surface of the casing, adapted to prevent centrifugal movements of the exhaust gases within said casing.

4. A closed exhaust silencer for internal combustion engines, comprising a casing, a resilient inlet pipe for admitting exhaust gases to said casing, a resilient outlet pipe for discharging exhaust gases from said casing, a nozzle on the inner end of each of said pipes, each of said nozzles being formed with a fiattened and elongated aperture, and being bent aside so as to be directed towards the side Walls of the casing, and longitudinal ribs 011 the internal surface of the casing, adapted to prevent centrifugal .movements or the exhaust gases within said casing.

In testimony whereof I have signed my name to this specification.

WILLFRIED FGRS-TEL. 

